Process for producing negatives from nontransparent originals for use in preparing printing plates



Patented Feb. 19, 1924.

entree stares aarsnrorrics,

MAX ULLNANN-,or ZWIGKAU, GERMANY, ASSIGNOR r KARL wnrvrn, or THE HAGUE,

. Nnrnnn-LANns.

rnoonss For, rn-onUoINe NEGATIVES rnoivi NoNrnANsrennN'r ORIGINALS For.use I INrRnranINs- PRINTING rrn'rns.

No Drawing.

Application filed April 14, 1921. Serial No. 461,454.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. I1.1313.) i I To aZZ whom it may concern:-

Be it known that 1, MAX ULLMANN, re-

' siding at 16 Talstrasse, Zwiclrau, Saxony,

Germany, have invented certain new and useful Improvements in Processesfor Produoing Negatives Originals for Use in Preparing Printing Plates(for which I havefiled applications in various countries foreign to theUnited States as follows: Germany, filed Jan. 7, 1920, patented Dec.Belgium, filed Dec. 2, 1920, application No. 253,982; Bohemia, filedNov. 20, 1920; Denmark, filed Oct. 28, 1920, patented June 23, 1922, No.29,873; Finland, filed Nov. 2, 1920, patented Sept. 2, 1921, No. 8,693;France, filed Nov. 2, 1920, patented July 8, 1921, No. 526,835; Holland,filed Nov. 27, 1920; Italy, filed Oct. 20, 1920, patented J an. 31,1922, No. 542/185; Luxemburg, filed Oct. 23, 1920, patented Oct. 23,1920, N 0. 11,985; Norway, filed Nov. 2, 1920, patented Aug. 22, 1921,No. 33,301; Austria, filed Oct. 21, 1920, application No. Oct. 28, 1920,application No. 14,994; Sweden, filed Nov. 16, 1920, application No.5432/20; Switzerland, filed Oct. 22, 1920, patented Sept. 15, 1921, No.91,898; Hungary, filed Oct. 29, 1920, patented Feb. 14, 1921, No.14,667; England, filed Jan. 7, 1921, application No. 725/21; Portugal,filed Feb. 26, 1921, patented Dec. 19, 1921, No. 12,104; Rumania, filedMarch 17, 1921, application No. 6,854; Spain, filed Nov. 22, 1920,patented Nov. 23, 1920, No. 76,313; Turkey, filed March 12, 1921,patented March 12, 1921, No. 3,178), of which the following is aspecification. V

Negatives for use in preparing printing plates may be prepared fromoriginals which are adapted to reflect light from a portion of theirsurfaces by the method more fully described in my Patent 1,436,125,dated Nov. 21, 1922, which embodies rendering a photographic imageproduced on a film of chromate colloid impervious to light by dyeing thesame with suitable soluble coal tar dyestufis. The preferred processthere described may be briefly summarized as follows. The translucentfilm of chromated colloid such as bichromated gelatin is laid on theoriginal which is to be copied with from Nontransparent 5873 20; Poland,filed opposite the white portions of the original are thus renderedinsolublefby the reflected light. The negative is then washed in wateror dilute acid to remove the portionsjwhich have not been so renderedinsoluble and after the washing the plate is dipped in one or moresuitable coloring or dyeing baths, for example, a bath of soluble analindye such as methyl violet, and the parts of the colloid layer remainingare thus colored and adapted to intercept light of an objectionablyactinic character In the practical utilization of this process.a-drawback is found in the fact that the image fades or bleeds whenleft in water. This results in indistinct pictures and re-coloringbecomes necessary. Furthermore, some difficulty is encountered when thenegative after drying is coated with an aqueous preparation, such, forinstance, as a gelatin solution, because of the danger that the coatingwill absorb the dyestuffs- These difiiculties are obviated by thepresent invention which provides for the conversion of the dyestuffs,whether basic or acid, into compounds insoluble in water. Y

It is known that basic or acid dyestufis may be rendered insoluble inwater by certain salts and acid or basic bodies accord-v ing to thecharacter of the particular dyestuff, usually an acid agentbeing adaptedfor use with a basic dyestufl, and vice versa. Thus diamido stilbenedisulphoacid-diphe- 1101 in an aqueous solution reacts with a diluteaqueous solution of pentamethyl-prosaniline to produce a precipitatethat is insoluble in water.

As a specific example of the manner in which my process may be carriedout I may mention the following. The negatives are produced in themanner described in my Patent 1,436,125 above referred to and the imagecolored by placing them in a dilute solution ofpentamethyl-p-rosaniline. colored negatives are then washed in a diluteaqueous solution of diamido-stilbenedisulphoaoiddiphenolt A. coloredlake The Y which is insoluble in Water is formed in the layer ofchromate colloid so that no fading takes place While the negative isimmersed in Water and if a Warm solution of gelatin is poured on to thenegative no coloring of this solution takes place.

The process herein disclosed is also disclosed in my copendin-gapplication constituting a continuation of this present application,Serial No. 573,660, filed July 8, 1922, which has eventuat'ed in Patent1,436,629, dated Nov. 24, 1922, in which application the transfernegative as an article is claimed.

Having thus described in detail the par ticular embodiment of myinvention here described, What I claim and desire to secure by LettersPatent is ,1. That method of producing negatives for use in thepreparation of printing plates 1 from originals which are adapted toreflect 2. That method of producing negatives for use in the preparationof printing plates from originals Which are adapted to. reflect lightfrom a portion of their surfaces characterized by rendering thephotographic image resistant to objectionably actinic light by treatmentwith a dilute solution of pentalnethyl-p-rosaniline and thereafterWashing it in a dilute aqueous solution ofdiamido-stilbene-disulphoacid-diphenol.

In testimony whereof I have signed my name to this specification.

MAX ULLMANN.

